Transport

Question 1

What are the two solutions surrounding the cell surface membrane?

Answer 1

Extracellular fluid and intracellular fluid/cytoplasm

Question 2

What is osmosis?

Answer 2

The movement of water from a solution with higher water potential to one with lower water potential through a selectively permeable membrane

Question 3

What happens if the water potential of the extracellular fluid is the same as that of the cell?

Answer 3

Osmosis will not occur

Question 4

What is cytosis?

Answer 4

An energy-consuming mechanism to transport large quantities of materials through gaps in the phospholipid bilayer

Question 5

What are the two modes of bulk transport?

Answer 5

• Endocytosis
• Exocytosis

Question 6

What is phagocytosis?

Answer 6

Process of engulfing large chunks of matter or particles by the cell

Question 7

What occurs during pinocytosis?

Answer 7

Liquid material or very small particles are engulfed by the cell

Question 8

What is receptor-mediated endocytosis?

Answer 8

A process where specialized protein molecules on the cell surface are involved in endocytosis

Question 9

What is the difference between active transport and facilitated transport?

Answer 9

Active transport moves substances against their concentration gradient; facilitated transport moves substances down their concentration gradient

Question 10

What is the sodium-glucose pump?

Answer 10

A mechanism that uses sodium ions to cotransport glucose into the cells against its concentration gradient

Question 11

What is the role of the sodium-potassium pump?

Answer 11

To control the osmotic balance of animal cells by transporting sodium out and potassium into the cells

Question 12

What are the effects of a hypotonic solution on an animal cell?

Answer 12

Water enters the cell, causing it to swell and potentially burst

Question 13

What happens to a plant cell in a hypertonic solution?

Answer 13

Water exits the cell, causing the cytoplasm to shrink and potentially lead to plasmolysis

Question 14

What does it mean for a solution to be isotonic?

Answer 14

The water potential is the same as that of the intracellular fluid, and osmosis will not occur

Question 15

Define the term ‘turgid’ in relation to plant cells.

Answer 15

A state where the cell is fully inflated with water, pushing against the cell wall

Question 16

What is plasmolysis?

Answer 16

The process where the cytoplasm shrinks and pulls away from the cell wall due to water loss

Question 17

What is the significance of the sodium-potassium pump?

Answer 17

It maintains cellular osmotic balance and is essential for vital processes

Question 18

What is the definition of diffusion?

Answer 18

The net movement of particles from a region of higher concentration to a region of lower concentration

Question 19

What are the four basic mechanisms a cell uses to regulate substance movement?

Answer 19

• Diffusion
• Osmosis
• Active Transport
• Cytosis

Question 20

What is the highest water potential value assigned to pure water?

Answer 20

Zero kilo Pascals (0 kPa)

Question 21

What is solute potential?

Answer 21

A measure of the change in water potential of a system due to the presence of solute molecules

Question 22

What occurs to water potential when solute is added to pure water?

Answer 22

It becomes negative as solute molecules restrict the movement of water molecules

Question 23

What is the difference between direct and indirect active transport?

Answer 23

Direct active transport requires ATP; indirect active transport does not

Question 24

What is the role of special carrier proteins in active transport?

Answer 24

They act as biological pumps to move substances against their concentration gradients

Question 25

What happens to a cell in an isotonic solution?

Answer 25

There is no net movement of water into or out of the cell

Question 26

What is the term for when a cell is just about to undergo plasmolysis?

Answer 26

Flaccid

Question 27

What is the effect of adding solute to water on its kinetic energy?

Answer 27

It reduces the kinetic energy of water molecules

Question 28

What is the relationship between concentration gradients and the direction of diffusion?

Answer 28

Particles move from areas of higher concentration to lower concentration

Question 29

Why does a cell need to exchange materials with its surrounding environment?

Answer 29

To maintain its highly ordered interior despite potentially disruptive surroundings.

Question 30

What are the processes involved in transport across the plasma membrane?

Answer 30

* Diffusion * Facilitated Diffusion * Osmosis * Active Transport * Cytosis (Endocytosis & Exocytosis)

Question 31

What is the main reason particles move from one region to another?

Answer 31

The existence of a concentration gradient, moving from higher to lower concentration until equilibrium is reached.

Question 32

What happens to particle movement once equilibrium is established?

Answer 32

Particles continue to move, but there is no net movement in any particular direction.

Question 33

What factors affect the rate of diffusion across the plasma membrane?

Answer 33

* Surface Area of the membrane * Concentration gradient * Thickness of membrane * Size & type of molecule or ion

Question 34

What occurs in a situation where pure water is separated from a dilute sugar solution by a selectively permeable membrane?

Answer 34

Water level in the pure water system declines while the water level in the dilute sugar solution increases.

Question 35

Define the term ‘Water Potential’.

Answer 35

A measure of the kinetic energy of water molecules, measured in kilo Pascals (kPa).

Question 36

What is osmosis?

Answer 36

The net movement of water molecules from a region of higher water potential to a region of lower water potential through a selectively permeable membrane.

Question 37

What are the key features of diffusion?

Answer 37

* Passive process, no energy required * Reversible, can occur in any direction if conditions are met.

Question 38

What is Simple Diffusion?

Answer 38

The unassisted crossing of the membrane by small molecules.

Question 39

What is Facilitated Diffusion?

Answer 39

The crossing of the membrane by molecules and ions with the assistance of transport proteins.

Question 40

List two similarities between Simple Diffusion and Facilitated Diffusion.

Answer 40

* No energy (ATP) needed * Molecules move down a concentration gradient.

Question 41

What is one difference between Simple Diffusion and Facilitated Diffusion?

Answer 41

Simple diffusion does not use transport proteins, while facilitated diffusion does.

Question 42

What are Channel Proteins?

Answer 42

Proteins that contain water-filled, hydrophilic channels or pores for ions to pass.

Question 43

What is the function of Carrier Proteins?

Answer 43

To bind specific large polar molecules for transport across the membrane.

Question 44

What is the role of aquaporins?

Answer 44

Channel proteins that allow the passage of water across the membrane.